Issues in Xunit.Assert.Collection - C#

Question

I have a Class Library, it contains the following Model and Method

Model:

public class Employee {
    public int EmpId { get; set; }
    public string Name { get; set; }
}

Method:

public class EmployeeService {
    public List<Employee> GetEmployee() {
        return new List<Employee>() {
            new Employee() { EmpId = 1, Name = "John" },
            new Employee() { EmpId = 2, Name = "Albert John" },
            new Employee() { EmpId = 3, Name = "Emma" },
        }.Where(m => m.Name.Contains("John")).ToList();
    }
}

I have a Test Method

[TestMethod()]
public void GetEmployeeTest() {
    EmployeeService obj = new EmployeeService();
    var result = obj.GetEmployee();
    Xunit.Assert.Collection<Employee>(result, m => Xunit.Assert.Contains("John",m.Name));
}

I got an Exception message

Assert.Collection() Failure
Collection: [Employee { EmpId = 1, Name = "John" }, Employee { EmpId = 2, Name = "Albert John" }]
Expected item count: 1
Actual item count:   2

My requirement is to check all the items.Name should contain the sub string "John". Kindly assist me how to check using Xunit.Assert.Collection

Answer 1

It appears that Assert.Collection only uses each element inspector once. So, for your test, the following works:

If the sequence result has exactly two elements:

[Fact]
public void GetEmployeeTest()
{
    EmployeeService obj = new EmployeeService();
    var result = obj.GetEmployee();

    Assert.Collection(result, item => Assert.Contains("John", item.Name),
                              item => Assert.Contains("John", item.Name));
}

If there are many elements, changing the Assert to

Assert.All(result, item => Assert.Contains("John", item.Name));

should give you the result you are expecting.